[mailto:owner-ietf-smime(_at_)mail(_dot_)imc(_dot_)org] On Behalf Of Paul
Sent: Monday, May 12, 2008 12:49 PM
To: Tony Capel
Subject: RE: S/MIME v3.2 IDs key size text (resend, no signature)
At 12:14 PM -0400 5/12/08, Tony Capel wrote:
Sean et al:
0 < key size < 512 : MAY but refer to security
512 <= key size < 1024 : SHOULD- but refer to security
1024 <= key size <= 2048 : MUST
2048 < key size : MAY but refer to security
Could you add verbs to your table? MAY what? SHOULD- what?
Not sure what Tony was thinking but I suggested that this go in 3850bis so
it would have been for receiving agents.
"A denial of service opportunity may exploitable by attackers who
provide an excessively large key, or a key selected to require
excessive cryptographic processing. One mitigation approach would
require that the corresponding public key certificate be
validated to a
trusted root [trust anchor] prior to use, thus ensuring that only
trusted public keys are used. However, some implementations
to perform signature verification (or data encryption) in
certificate validation, or even if certificate validation fails. In
such cases, measures should be included to limit the impact, for
example by limiting cryptographic processing time or requiring
certificate validation prior to the use of large keys."
Regardless of small key size issue, I think text like this
would be a good addition to the Security Considerations
section of many documents.
I had something similar in the -02 version, but I'll swap out that text for